Arrangements having at least one hydraulic actuator are used, for example, in automatic transmissions of motor vehicles but not exclusively. The hydraulic actuators are here needed to build up and/or to maintain pressures or difference pressures.
It is known to realize hydraulic actuators as magnetic valves.
The actuation of magnetic valves is effected by the activation or deactivation of an electromagnet provided in the valve. When electromagnets are activated and deactivated, current flows through the coils thereof and this causes the movement of an armature, more specifically, the pull-in or release (or reset) of an armature. This armature is operatively connected to the closure element of the valve and this element is moved with the armature. The position of the armature and of the closure element is essentially retained unchanged until the current is switched off. After the current is cut off, the armature and the closure element return to a defined start position.
The magnetic valves are actuated by a control apparatus contained within the arrangement. This control apparatus is an electronic transmission control apparatus or EGS if the magnetic valves are parts of a motor vehicle transmission. The control apparatus is therefore relatively large and must be dimensioned for high use and loss powers. This, in turn, makes the suitable accommodation of the control apparatus in the motor vehicle difficult and makes the arrangement complicated and inconvenient (or hard to handle).